1. Field of the Invention
This invention relates generally to beverage dispensers for dispensing semi-frozen slush beverages, and more particularly to a slush beverage dispensing system having a base unit housing a motor connected with an electrical power source and a gas pressurizing member, and an insulated slush dispensing vessel removably supported on the base unit with an interior rotating agitator releasably connected to the motor when the vessel is supported on the base, and such a system capable of use as a stand-alone system or as a self-contained portable system housed in a backpack supported on the back of a vendor.
2. Brief Description of the Prior Art
"Slush" beverages, as the term is used herein, are defined as a thick semi-frozen beverage having a semi-solid ice consistancy, similar to partly melted snow, and consist of a mixture of flavored liquid or syrup, frozen crystals of the liquid or syrup, and other materials. Examples of "slush" beverages are frozen cocktails, such as a "frozen margarita" or "daquiri", and flavored soft drinks or carbonated drinks, such as the popular slush beverage known commercially as an "icee" or a "slurpy" which are available at convenience stores and fast food chains. The slush type beverages are normally dispensed from a special machine at a fixed location and thus are not widely vended at sports stadiums, and other locations remote from the special machine required to make the beverages.
Because of the viscosity of the frozen semi-solid ice crystals, prior art and conventional "liquid" beverage dispensors are not suitable for storing and dispensing a "slush" beverage, because there is no provision for agitating the slush to maintain its consistancy and the small orifices of the conventional "liquid" dispensers" will freeze up or become plugged with the frozen ice crystals. Also, conventional metal vessels or containers, if uninsulated, may develop a thin layer of ice on their exterior due to the temperature of the semi-frozen slush.
Portable liquid beverage dispensers adapted to be transported on the back of a vendor by use of a body harness are also known in the art, as disclosed by way of example, in U.S. Pat. No. 2,684,787 to Charpiat and U.S. Pat. No. 2,808,965 to Grafia et al. Such portable dispensers include a tank made of rigid material enclosing a liquid storing chamber from which the beverage is dispensed and into which the beverage is charged through a reloading valve connected to the bottom of the tank. The beverage is accordingly dispensed under a gravitational pressure head. To assist in dispensing of the beverage, particularly when the liquid within the tank becomes depleted, the tank chamber may be internally pressurized with air by means of a pump as disclosed, for example, in U.S. Pat. No. 3,147,889 to Dolgin.
Motsenbocker, U.S. Pat. No. 4,420,097 discloses a portable liquid dispenser having an insulated carring case which contains a first flexible container and a second flexible container positioned therein. A freezable liquid is contained ir the second container and the liquid to be dispensed is contained in the first container in contact with the surface of the container with the frozen liquid to cool the liquid to be dispensed. The liquid is dispensed under gravitational pressure.
Boxer et al, U.S. Pat. No. 4,526,298 discloses a flexible water bag or pouch which may be insulated that is carried on shoulder straps similar to a back pack. The liquid is dispensed by a squeeze type dispensing nozzle.
Ash, U.S. Pat. Nos. 4,896,402 and 5,199,609, disclose a rigid dispenser tank with an outer insulated jacket and an interior flexible bladder which is pressurized to maintain the liquid under pressure.
Sims, U.S. Pat. No. 3,662,929 discloses a non-insulated rigid container with interior flexible bladder connected to a source of fluid pressure. A fluid substance to be dispensed is stored in the rigid container and the flexible bladder is inflated to discharge the fluid substance under pressure.
Uhlig, U.S. Pat. No. 4,098,434 discloses a non-insulated fluid product dispenser having first container and a second flexible container positioned inside the first container. Fluid to be dispensed is contained in one of the containers and fluid under pressure is introduced into the other container to urge the product fluid through a dispensing nozzle or opening.
Cornelius, U.S. Pat. No. 2,513,455 discloses a non-insulated rigid dispenser tank with an interior flexible bladder connected to a gas container. Fluid to be dispensed is stored in the rigid dispenser tank. The gas fed to the bladder condenses at the pressure and temperature at which the fluid in the container is to be discharged.
Shy, U.S. Pat. No. 4,300,705 discloses a compressed vacuum insulated bottle which operates by siphonage and compression of an elastic pouch in the top of the bottle stopper to siphon boiling water into the elastic pouch and then to drain off the boiling water by compression.
Billet, U.S. Pat. No. 4,921,143 discloses a portable beverage dispenser carried on the back of a vendor and has an insulated tank for containing a beverage, a hand pump for manually pressurizing the contents, and a thermally insulated dispensing hose.
Billet, U.S. Pat. No. 5,385,275 discloses a portable beverage dispenser carried on the back of a vendor and has an insulated dispensing chamber for containing a carbonated beverage, a thermally insulated dispensing hose, and a tank holding liquid gas for pressurizing the dispensing chamber.
Credle, Jr., et al, U.S. Pat. No. 5,529,220 discloses a portable beverage dispenser system a plurality of bottles of premix beverage connected in series with a CO.sub.2 cylinder carried in an insulated pack supported on the shoulder of a vendor.
Cox et al, U.S. Pat. No. 5,588,558 discloses a stationary liquid beverage dispenser for displaying and dispensing liquid beverages which includes a liquid containing dispensing chamber, a pump for transferring amounts of the beverage from a storage chamber to the dispensing chamber, and a optical level sensor for activating the pump when the liquid level falls below a predetermined level.
The above described "liquid" beverage dispensers are not suitable for use for storing and dispensing a "slush" beverage, because there is no provision for agitating the slush to maintain its consistancy and the small orifices and check valves in the dispensing system of the conventional "liquid" dispensers" will freeze up or become plugged with the frozen ice crystals. Also, the conventional uninsulated metal vessels or containers may develop a thin layer of ice on their exterior due to the temperature of the semi-frozen slush. Those systems using a pressurized tank containing a supply of gas for pressuring the beverage container are heavy to transport and require frequent replacement of the pressurized gas tank.
The present invention is distinguished over the prior art in general, and these patents in particular, by a slush beverage dispensing system wherein a semi-frozen slush beverage is contained in a thermally insulated vessel which is removably supported on a base unit containing a gas pressurizing mechanism and a motor connected to an electrical source. The gas pressurizing mechanism is controlled by a pressure sensor to maintain pressure on the beverage inside the vessel and an agitator contained within the vessel is releasably connected to the motor shaft when the vessel is supported on the base unit and is operated to swirl the beverage to prevent the semi-frozen slush beverage from separating. A slush delivery valve on the vessel side wall has an outlet end to which a dispensing nozzle or a flexible insulated hose having a dispensing nozzle at its outer end may be releasably connected for dispensing the beverage. The power source may be a battery disposed in the base unit and the base unit may be provided with a battery recharging receptical and associated circuitry. The base unit may also be provided with circuitry and a switch for bypassing the pressurizing mechanism to allow gravity dispensing. In a stand-alone embodiment the base unit and vessel may be supported on a counter top or in a cabinet and, in a portable embodiment, the base unit and vessel are contained within a backpack worn by a vendor.